Sound absorbing grille



United States Patent [72] Inventor Reynold C. King Jasper, Indiana [21 Appl. No. 736,078 [22] Filed June 11, 1968 [45] Patented Nov. 3, 1970 [731 Assignee Emerson Electric Co.

St. Louis, Missouri a corporation of Missouri [54] SOUND ABSORBING GRILLE 7 Claims, 3 Drawing Figs.

[52] U.S. Cl 181/50,

- 98/40 [51] 1nt.Cl. F0111 1/10;

F24f 7/02, F241 7/06 [50] Field of Search 181/42, 50; 98/40 [56] References Cited UNITED STATES PATENTS 1,934,463 11/1933 Hartsock 181/50 2,587,565 2/1952 Yonkers 1'81/50X Isl/ 0 2,644,389 771953 Dauphinee;

Primary Examiner- Robert S.'Ward, Jr. AttarneyChar1es E, Markham ABSTRACT: A sound absorbing grille covering a wall opening leading to an electric fan mounted in the wall comprising a perforated disc member supported by the fan motor overlying the opening and having a rim portion lying against the wall and an imperforate disc member overlying the apertured member and being spaced therefrom whereby air flow to or from the opening passes between the peripheral portions of the spaced members, the rim portion of the imperforate member being detachably connected to the rim portion of the perforated member and the imperforate member having a sound absorbing-lining facing the wall opening to intercept fan motor sound issuing therefrom.

SOUND ABSORBING GRILLE This invention relates to a grille covering an opening in a wall or ceiling through which air is caused to flow by a fan mounted within the wall or ceiling and in particular to a construction which effectively prevents fan noise from entering the room.

Open grilles which-permit or more or less axial air flow between a room and a wall mounted fan alsopermit fan noise to enter the room substantially uninterrupted,

An object of the present invention is to provide a generally new and improved grille of pleasing appearance for covering an air flow opening in a wall or ceiling which permits a free flow of air to or from a room while effectively intercepting and absorbing sound issuing from the wall opening.

More specifically, it is an object to provide a sound absorbing grille for covering an air flow opening in the ceiling or wall of a room leading to an air moving fan mounted in the wall, the grille comprising a disc having a centrally perforated portion overlying the opening and having a rim portion adapted to be mounted in fixed position against wall or ceiling and a concentric imperforate disc detachably connected to the rim portion of the perforated disc and being spaced axially therefrom, whereby air entering or issuing from the wall opening passes between peripheral portions of the spaced discs, and the imperforate disc having a sound absorbing surface facing the wall opening.

Further objects and advantages will become apparent from the following description when read in connection with the accompanying drawing.

in the drawing:

FIG. 1 is a cross-sectional view of a sound absorbing grille constructed in accordance with the present invention, shown in association with a ceiling mounted exhaust fan;

H6. 2 is a partial plan view of the centrally perforated disc member, looking along line 2-2 of PK]. 1', and

PK 3 is an enlarged fragmentary cross-scctional view of rim portions of the perforate and imperfornte discs showing the means for detachably connecting the lmperforate disc to the perforate disc in clearer detail.

Referring to FIG. 1, numeral indicates a ceiling mounted, motor driven, exhaust fan having a motor 12, which fan and motor assembly are supported in a sheet metal volute 14. The volute 14, being supported in any suitable manner within the ceiling structure, has a lower central opening 16 defined by a downwardly formed rim 18 which fits the ceiling opening 20. The fan and motor assembly includes a mounting ring 22 to which motor 12 is connected by straps 24 and bolts 25, and the mounting ring 22 being concentrically positioned in the volute opening 16 has a flange 26 attached to the volute by screws 28 and straps 30. The straps 30 are welded to the volute, and pliable, vibration absorbing washers 32 are inserted between the straps 30 and the mounting flange 26.

The motorv '12 includes a central, downwardly extending, threaded stud 34 which supports a centrally perforated disc member 36. Disc 36 is formed as a sheet metal stamping and has a flat portion 38 and a rim portion 40. The central portion 38 has three sectional perforations 42 divided by integrally formed radial members 44 which support an integrally formed central portion 46. The central portion 46 is perforated to receive a pliable vibration damping grommet 48 which, in turn, receives the threaded-motor stud 34. The rim portion 40 of disc 36 has a downwardly formed annular rib 52 and an upwardly and outwardly formed peripheral portion 54.

A thick washer 56 of easily compressible material, such as a flexible, foamed, synthetic resin, is inserted between the rim portion 40 of disc 36 and the finished ceiling, and a wing nut 58 on stud 34 is tightened to lightly compress the washer 56, the washer being slightly thicker than the length of the turned up peripheral portion 54.-Connected at one end to the annular rib 52 by rivets 60 are four, circularly spaced, spring clips 62 extending radially outward and slightly downward from the rib 52. The outer free ends of spring clips 62 are curled downward to provide rounded ends.

Supported on the spring clips 62 is an imperforate disc 64 formed as a sheet metal stamping. The disc 64 has a flat central portion 66 somewhat larger in diameter than the perforated area of disc 36 and an upwardly and outwardly formed rim portion 68, the edge 70 of which is formed inward at substantially and overlies the free end portions of spring clips 62 thereby to be supported by and detachably connected to the rim portion of disc 36. Attached to and substantially covering the upper surface of the flat, central portion 66 of the disc 64, as by gluing, is a thick disc 72 of sound absorbing material and similarly attached to and substantially covering the inner surface of the rim portion 68 is a strip 74 of similar sound absorbing material.

The sound absorbing disc 72 and strip 74 may be constructed of any suitable sound absorbing material which may be fastened to imperforate disc 64 in any suitable manner. in a preferred construction, these members are constructed of an open cell, porous surface, foamed, synthetic, plastic material, such as flexible urethane foam, and are glued to the surface disc 64. It is to be further understood that the imperforate disc 64 may be constructed of suitable soundproofing material having the required rigidity for the purpose and including a suitable metal attaching band thereon for cooperation with the spring clips 62.

lclaim:

l. A sound absorbing grille forcovering an opening in a wall in which an exhaust fan is mounted adjacent the opening comprising, a first disc member having a central perforated portion adapted to overlie the wall opening and an imperforate rim portion adapted .to lie against the wall surrounding the wall opening, support means adapted to be mounted in the wall, means for connecting said first disc member to said support means, with said central perforated portion thereof overlying the wall opening and with said rim portion thereof lying against the wall surrounding the wall opening, a second, imperforate, disc member overlying said first disc member and spaced therefrom, peripherally spaced elements connecting said second, imperforatc, disc member to said first disc member and supporting it in outward spaced relationship thereto, said second, imperforatc, disc member being of sufficient size to effect a substantially 90directional change in air flow entering the wall through the wall opening, and said second, imperforatc, disc member having a porous, sound absorbing surface facing said first, perforated, disc member.

2. An exhaust fan assembly including a motor adapted to be mounted in a wall adjacent a wall opening and a sound absorbing grille supported by the exhaust fan assembly and overlying the wall opening, the grille comprising a first disc member having a perforated central portion adapted to overlie the wall opening and an imperforate rim portion adapted to lie against the wall surrounding the opening, screw threaded means connecting the center of said first disc member to said exhaust fan assembly and operative when tightened to draw said rim portion thereof flrmly against the wall, a second disc member overlying said first disc member and outwardly spaced therefrom, peripherally spaced elements detachably connecting peripheral portions of said disc members and supporting said second disc member on said first disc member in outward spaced relationship therewith, said disc members being approximately the same size whereby air flow entering the wall between said disc members and through the wall opening makes a right angle turn, and said second disc member having a porous, sound absorbing surface facing said first, perforated, disc member, thereby to intercept sound emanating from said exhaust fan and motor.

3. The exhaust fan and grille claimed in claim 2 in which said screw threaded connecting means comprises a threaded stud projecting from saidfan motor centrally through the wall opening and passing through a central aperture in said first, perforated, disc member, and a nut on said stud which when tightened drawssaid first disc member against the wall.

4. The exhaust fan and grille claimed in claim 2 in which said imperforate rim portion surrounding said central perforated portion of said first disc member has sufficient width to overlie a substantial portion of the wall opening.

5. The exhaust fan and grille claimed in claim 3 in which a soft rubberlike grommet inserted in said central aperture in said first disc member and tightly surrounding said stud insulates said first disc member from fan or motor vibrations and when attaching or detaching said second, imperforate, disc member. 1

7. A sound absorbing grille as claimed in claim 1 in which said rim portion of said first, perforated,.disc member has a flat annular portion parallel to the wall and a surrounding angularly formed portion forming a bezel, the peripheral edge of which is adapted to lie against the wall, and in which a relatively thick, easily compressible, annular member lying against said flat annular portion is adapted to be compressed between said rim portion and the wall, and in which said rneans'for con meeting said first, perforated, disc member to said support means comprises screw threaded means which when tightened compresses a said compressible annular member. 

